This invention relates to an electronic metronome. More particularly, the present invention is directed to a metronome having a stepper motor driving system which attains constant torque-frequency characteristics of the stepper motor to thereby obtain an energy saving in the operation of the electronic metronome.
A variety of metronomes have been used conventionally. A typical construction is the mechanical metronome. Since the mechanical metronome uses a spring as the driving force, it has the drawback that the spring must be wound whenever the metronome is used.
An electronic metronome that has been used recently displays tempo and rhythm by means of sound and light, but its visible effect is no improvement over the conventional baton.
In order to obtain the baton effect described above, another kind of electronic metronome has been developed which uses an electric meter in combination with sound and light. However, the signal tracking characteristics of the pointer in the electric meter are not adequate, and this problem becomes particularly evident as the tempo or rhythm increases, hence, satisfactory characteristics can not be obtained. In connection with the electric meter, a large meter pointer can not be used due to the relatively small driving force; hence, it has been necessary to use a small meter pointer. Therefore, the effect of the meter was no improvement over the conventional baton.
In conjunction with the characteristics of the driving force of a stepper motor, the torque-frequency characteristics change remarkably depending upon the voltage parameter as shown in FIG. 3. Therefore, if the motor is always driven at a predetermined pulse width, the battery life is shortened, and irritating noise is present because excessive load is applied to the baton, and the service life of the motor is consequently shortened.